//
// Copyright 2016 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
//    names, trademarks, service marks, or product names of the Licensor
//    and its affiliates, except as required to comply with Section 4(c) of
//    the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
#include "pxr/imaging/cameraUtil/screenWindowParameters.h"

PXR_NAMESPACE_OPEN_SCOPE


CameraUtilScreenWindowParameters::CameraUtilScreenWindowParameters(
    const GfCamera &camera, GfCamera::FOVDirection fitDirection)
    : _screenWindow(
        - camera.GetHorizontalAperture()
                + 2 * camera.GetHorizontalApertureOffset(),
        + camera.GetHorizontalAperture()
                + 2 * camera.GetHorizontalApertureOffset(),
        - camera.GetVerticalAperture()
                + 2 * camera.GetVerticalApertureOffset(),
        + camera.GetVerticalAperture()
                + 2 * camera.GetVerticalApertureOffset()),
      _fieldOfView(camera.GetFieldOfView(fitDirection))
{
    if (camera.GetProjection() == GfCamera::Perspective) {
        const double denom =
            (fitDirection == GfCamera::FOVHorizontal) ?
               camera.GetHorizontalAperture() : camera.GetVerticalAperture();
        if (denom != 0.0) {
            _screenWindow /= denom;
        }
    } else {
        _screenWindow *= GfCamera::APERTURE_UNIT / 2.0;
    }

    static const GfMatrix4d zFlip(GfVec4d(1,1,-1,1));
    _zFacingViewMatrix = (zFlip * camera.GetTransform()).GetInverse();
}

PXR_NAMESPACE_CLOSE_SCOPE

